7 Advantages of Vertical Axis Wind Turbines (VAWT)
Although being less represented in the wind energy industry compared to horizontal axis wind turbines, vertical axis wind turbines have strong advantages that continuously attract engineers to research and explore their potentials in design, efficiency, and application. While the development of horizontal axis wind turbines is already mature, it is clear that the next industry trend will shift its focus to vertical axis wind turbines.
The advantages of vertical axis wind turbines
There are a few characteristics and advantages of vertical axis wind turbines that make them perfect choices for certain geographical conditions and wind energy applications.
1. Omnidirectional Natural of the Rotor
Vertical axis wind turbines are equipped with rotor blades that can pick up wind coming from any direction. Unlike so, horizontal axis wind turbines need to face the direction of the wind to operate. They rely on the yaw system to orientate the rotor in order to capture wind.
Due to this difference in operation mechanism, vertical axis wind turbines can be used to generate power even in unstable weather conditions such as turbulent, gusty wind. They also function well in mountain and coastal areas.
2. Closer Spacing
In a horizontal axis wind turbine power plant, the general rule-of-thumb for spacing is to place the turbines 5 diameters apart across the wind, and about 10 diameters apart extending downwind. This is to avoid disruption of air flow and reduction in wind speed caused by one turbine to another, which affects the power output of neighboring units.
Compared to horizontal axis wind turbines, vertical axis wind turbines can be grouped closer together in a wind power plant. This is because vertical axis wind turbines function well in turbulent wind. They are generally spaced 4 to 6 diameters apart.
Closer spacing would allow a wind power plant to capture more energy per square meter of land. Generally speaking, a single vertical axis wind turbine is not as energy-efficient as an individual horizontal axis wind turbine. However, a 2017 research led by then Stanford University mechanical engineering doctoral candidate, Anna Craig, had a different conclusion. The research suggested that a group of closely-spaced vertical axis wind turbines have the potential to generate as much as 10 times more power per unit of land compared to a group of widely-spaced horizontal axis wind turbines. The research is published in the Journal of Renewable and Sustainable Energy.
3. Lower Starting Wind Speed
Vertical axis wind turbines have a lower starting wind speed compared to the horizontal axis models. The necessary starting wind speed for a typical vertical axis wind turbine is 2 to 3 m/s. This allows vertical axis wind turbines to generate electricity even when incoming wind is relatively weaker. Although the amount of electricity generated at lower wind speeds is much smaller, it is still better than having a wind turbine that is not able to harvest weaker incoming wind.
4. Lower Environmental Harm
Generally smaller, the size of vertical axis wind turbines brings along a few advantages, one of which being the low environmental harm. Because they are built closely around the shaft, the rotor blades of vertical axis wind turbines do not create huge, extend drop shadows. The blades are also easier to spot for birds and other flying animals, decreasing the chance of animal casualty.
Furthermore, vertical axis wind turbines operate with quieter noise emission, so they do not disturb people in residential neighborhoods.
5. Easier Installation and Maintenance
The second advantage thanks to the smaller size of vertical axis wind turbines is that they are easier to transport, set up, and maintain. For example, all parts of one LuvSide turbine can be delivered with a single truck with a 6-meter long storage space. Maintenance workers do not have to climb as high to reach parts of the turbine because the major components, such as the generators, are built closer to the ground.
6. Less Restricted Installation
Another advantage coming with its size is that vertical axis wind turbines are more permissible where taller structures are prohibited. While local regulations vary, in Germany, wind turbines shorter than 50 meter are approved for installation in most federal states, according to the German Bundesverband Kleinwindanlagen.
7. Striking Representation
Last but not least, the modern geometrical designs of vertical axis wind turbines allow them to operate with elegance and create smooth visual flow. Their appearance is perfectly complementary to buildings, campuses, and parks. Utilizing wind power to generate electricity, they also speak directly about the sustainable values of an organization or community with strong visual impressions.
The power runner in certain environment
Overall, vertical axis wind turbines produce power for smaller-scale applications, particularly in unstable windy regions or urban areas. The choice of whether to go with vertical axis wind turbines should strongly depend on your local environment and purpose of power generation.